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MG MGB GT V8 Factory Originals Technical - SU carb designed to incline ?


I have a B GT V8 with the factory carb set up. In order to get the engine to 200bhp I need to do some flow work to the carbs.

Rather than change the original carbs, I thought I might buy a pair of SUs from ebay and modfiy those. However most HIF6's from V8s are designed to be used inclined on the Land Rover type intake. will a set of these work horizontaly on a B GT type intake?

I'm aware that the central float chamber makes them resistant to lateraly g loads, but unsure if they will work permenantly once moved from the incline position to the horizontal.

J E G Eastwood 1

As long as you have ample fuel pressure, I can't imagine why they wouldn't work in a "level" installation. The way the fuel path is layed out, it shouldn't matter. I don't think the air filters would fit a level installation in a stock B though (not that it matters.)
Jeff Schlemmer


I can't quite understand why you need to do anything to the standard carbs?

I am running 230 bhp on standard carbs; the joy is the engine looks standard, and has lots of low down torque.
Nigel Steward


What's your displacement and what have you done to get 230bhp?
Stuart Robson


The HIF6 is recognised as being capable of supporting airflow sufficient to make up to ~90bhp, before the pressure drop across it becomes significant. At power levels above 90bhp, there are small, then greater power losses due to the flow potential. Certainly 115/carb is possible, but you might see another 2-4bhp/carb with a 2inch carb or a flowed HIF 6.

Info is taken from David Vizard's 'How to tune the A series' book. I had planned to do the mod of reducing the throttle shaft to 1/2 thickness, and tidying the transition before and after the bridge, again all simple mods taken from David's book.
J E G Eastwood 1

Using different HIF6's should be fine, just make sure your overflow isn't overflowing. You may have to use the original pistons and dashpots as I believe they are shorter than the standard v8 ones. I would like to see what you are planning on doing as I have a factory setup on my conversion and have thought about cleaning up the flow path through the carbs.


Ditto Stuart's comment; what is the rest of your set up to achieve 230 via standard carbs.

Would be of interest, thanks.

J E G Eastwood 1

This thread was discussed between 02/11/2005 and 05/11/2005

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